Thread-tensioning means for sewing machines



July 22 1924.,

A. AQMERRETT THREAD TENSIONING MEANS FOR SEWING- MACHINES Filed Feb. 10, 1921 INVENTOR. m a yaw/Lag,

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A TTORNEYZQ Patented July 22, 192

UNITED ST ARTHUR A. MEBR-ITT, OF PROVIDENCE, RI-IODE ISLAND, ASSIGNOR. TO WILLCOX 8r.

GIBBS SEWING IVIACHINE CO., OF NEW YORK,- N. Y., A CORPORATION OF NEW YQRK;

THREAD-TENSIONING MEANS FOR SE K/ING- MAGHINE S.

Application filed February 10, 1921. Serial No. 43,932.

To all whom it may concern:

Be it known that I, ARTHUR A. MERRITT, a citizen of the United States, and a resident of Providence, Rhode Island, have invented new and useful Improvements in Thread-Tensioning Means for Sewing Machines, which invention is fully set forth in the following specification.

This invention relates to thread-tensioning means for sewing machines. One object is the provision of practicable and efficient adjustable thread-tensioning means whereby any desired tension may be imposed upon the thread according to conditions encountered. A further object is the provision of thread-tensioning means for a plurality of threads adapted to be'simultaneously thrown into and out of operation as to all of said threads collectively and adjustable to individually determine the tension for each thread irrespective of the tension for other threads. A further object is the provision of such means in which *the collective releasing and applying of the tension upon the plurality of threads does not disturb the individual. tension adjustment for each thread.

Though designed especially for use in What are known commercially as the Willcog. & Gibbs" Sewing Machine Companys Flatlock machine, shown for example in patent to me No. 1,041,652, dated October 15, 1912, and Feldlock machine of patent to me No. 1,253,507, dated January 15, 1918, the thread-tensioning means of this inventionmay be used in othertypes of sewing machines and especially wherever it is desired to individually, or separately, tension threads under conditions such as or similar to those hereinafterset forth. At the left hand end of Fig. 49 and in Fig. 52 (Sheets 23 and 24) of the aforesaid Patent 1,041,652 there are shown four pairs of tension disks between which four needle threads pass, and another pair of tension disks between which a cross-thread passes, all of said disks for the needle threads being pressed together by a common spring whereby the tension is approximately equal ized upon the fourneedle threads. The lifting of the presser-foot automatically actuates an arm (68'? in Fig. 49) which releases or throws the tension means out of action upon all the threads simultaneously amin n ates th t end tion anti the presser-foot is again lowered. Adjustment A of the tension for the four needle threads in that structure is effected by adjustment of the tension of the single spring common to the four sets of disks for the four needle threads. That is, there is a tension adjustis now believed to be the preferredembodi ment thereof illustrated in the accompanying drawing, wherein Fig. 1 is a front elevation with the .ma chine casing or frame in section;

Fig. 2 is a vertical transverse section. through the thread-tensioning means shown in Fig. 1;

Fig. 3 is a front elevation thread-tensioning means;

. Fig. 4 is a sectional view on line lt of F ig. 2'; and

Fig. 5 is a detail view of one of the parts.

In Fig. 1 there is shown at 10a fragment of the top wall of the hollow bridge of the frame of a sewing machine such. as shown in the aforesaidPatent 1,041,652, and simi larly at 11 there is shown a fragment of the wall ofa hollow standard at one end ofsaid machine frame. A bracket or frame, upon which the .threadtensioning 'means are mounted, aspresently described, comprises a basesection or plate 12, an upright section or wall 13, and an end-plate or wall 14. Said base 12 seats against the top of wall 10 and is secured thereto by screws .15, while end-plate 1 1 fits overand closes. an opening in wall 11, as shown in Fig. 1. A horizontally disposed bar 16 is longitudinally movable in a bearing opening through base-plate 12 and .at its left hand end car-. ries an upright arm 17 connected at. its upper end to the end of a rod 18 longitudinally movable in a horizontal bearing opening extending the entire lengthof upright. Wall .14 A springlQ earl-Winding rlt of parts of the bears atone end against plate 14 and atits other end against the hub of arm 17 around bar 16, the spring thus tending to move said bar, its arm 17 and rod 18, to the left in Fig. 1, such movement being limited by a stop in 20 through bar 16 adapted to contact the end of base-plate 12. '21 is an upstanding swinging arm automatically actuated by the lifting and lowering of the presserefootfortmanipulation of the work under the latter. The beveled surface at the tuaper end ofarm 21 actuates the end of bar 16 to rmove the same and rod 1Stoward the right in Fig. 1 against the tension of spring 19 when the presserfoot is liftedbyits lifting -mea-ns.

The upright wall 13 is recessed .at'22, said recess intercepting the bearingopening for rodl8'andiexposing that portion of said rod which traverses said. recess, as clearly shown. Apresser-plate or anvil 23 has an upstanding extension positioned between ,twolugs 241, 24 .on plate 13 at opposite edgesrespectively of the recess 22. A pivot pin 25 through-the lugs 24 and the .eXtensiono'f presser-plate or anvil 23, hinges the latter tothe bracket or frame of the thread-tensioning means. A lug26 on the underside of presser-plate .23 projects intorecess 22 of wall 13 and contacts one or the other of two flattened surfaces 27.28 of rod 18, said surfaces being at different elevations with respect to each other and. the axis of the rod with an interveningflattened inclined surface 29.

Thestructure as illustrated is adapted to accommodate the threads, the .four needle threads a, Z), 0 and (Z, and cross thread 6. Hence, five flat or blade springs 30 are shown, each adapted at its free end to ;.press one .of thethreads against the presserrplate 23 in tensioning said thread. Since these springs and the associated supporting :and adjusting means foreach spring areall alike, a description-as to one will suffice forall. As clearly shown .in longitudinal section, spring 30 is bent nearits middle forming it into two approximately parallel offset-sections, .the lower of said section at-the free end of the spring bearingagainst presserplatel23 and being slightly upturned .at its free extremity. At its-upper extension the springis secured by a screw-31 torthe underside ofan angle-arm orbracket piece which. is in turn secured=to the upperedge of wall 13 bya screw33. An elongated threadeyelet .or tubular thread .guide 3 1 projects through angle-arm 32. 11 tension adjusting screwk35. is threaded through the free end, of angle-arm '32, bears its inner end against bladespring iiO, and atits outer'end hasa milled head tosfac'ilitate gripping with the fingers in: turning the screw for adjustment. The .screw is..splitilongitudinally to give a spreading spring againstthethreaded wall of its opening-and thereby maintain the position to which it is adjusted. 36 are thread guiding hooks, one for each of the five threads, of a construction more fully described in patent-to me No. 1,0411,65'6, dated Oct. 15, 1912. 37 is a wire spring secured at one'en'd by a set screw 38 to the anglearm 32 at the extreme left, and at its free end positioned to bear against the four needle threads for the purpose descrieed in Osterhout Patentllo. 1,134,482 dated Apr. 6, 1915, with reference to-the similar spring 40 of said patent.

V In operation, each thread, for example thread (1., passes from a source of supply through its corresponding thread guide at, thence between its spring-3O and the presserplate23 and throughits hoolr3l3and under spring 37. Vith thesewing machine in operation and its presser-ffoot in engagement with the work, the spring'19'holds the bar 16 and rod 18 in the position shown in the drawings, with thepin 20 of bar 16in con tact with the end surface of prate 12,- and the lug 26 seated against the flattened surface 28 of 'the rod 18 and the presser-plate 23 thus held up in its active position with rela tion to springs '30 and in which position tension is imposed upon the threads passing between said springs and plate. The tension of any-spring upon its thread may be adjusted'by adjustment of the corresponding screws whereby the-threads maybe sinii larly or differently tensioned as desired. Lifting of the presser-foot to withdraw or introduce work thereundere-actuates arm 21 to move bar 16 and rod 18 to the right against the tension of spring 19, thereby bringing the flattened surface 27 of rod '18 opposite lug 26 andjpermitting theqplate to swing at its lower end by gravity slightly downward (towardrthe-right Fig. '2) sufficient to release thegripping of the threads between the springs'30 and presser-plate 23 and hence approximately simultaneously releasing .the tension upon all the threads. Subsequent lowering of the ;presser foot againmoves the rod 18 'an'd plate23 to the position in which they are shown in the drawing .thereby reapplying the tension (determined as to each threadby the position to which corresponding ser is adjusted) upon all of the threads.

What Iclaim is:

1. In thread-tensioning-1neans for sewing machines. the .combin ationof ,presserplat-e or anvil ,member. a plurality of tension springs for directlyengagi-ng and separate lyipressing threads into direct contact with the surface of said. anvil memberto tension said threads, adjusting means for separately determining the degree of pressure to be exerted by each spring-upon its thread, and meansoperableito effect-movement of the nv l mem out t nt a with relation to the tension springs to simultaneously release or impose tension upon all of the threads.

2. In thread-tensioning means for sewing machines, the combination of a pivotally supported presser plate or anvil member, a plurality of tension springs for separately pressing threads against said plate to tension said threads, adjusting means for separately determining the degree of pressure to be exerted by each spring upon its thread, and means operable to swing saidpresser plate on its pivot out of and into active position with relation to the tension springs to simultaneously release or impose tension upon all of the threads.

3. In thread-tensioning means for sewing machines, the combination of a pivotally supported presser plate or anvil member, a plurality of tension springs forseparately pressing threads against said plate to tension said threads, adjusting means for separately determining the degree of pressure to be exerted by each spring upon its thread, and means operating automatically upon raising and lowering of the sewing machine presser foot to swing said presser plate on its pivot out of and into active position with relation to the tension springs to simultaneously release or impose tension upon all of the threads.

4. In thread-tensioning means for sewing machines, the combination of a presser plate or anvil member, a plurality of tension springs for directly engaging and separately pressing threads into direct contact with the surface of said plate to tension the threads, and means operable to move said plate into active position with relation to said tension springs and thereby apply or release tension upon all of the threads together.

5. In thread-tensioning means for sewing machines, the combination of a pivotally mounted presser plate or anvil member, a plurality of tension members for separately pressing threads against said plate to tension the threads, and means operable to move said plate on its pivot into and out of active position with relation to said tension members collectively to thereby apply or release tension upon all of the threads together.

6. In thread-tensioning means for sewing machinesor the like, the combination of a presser plate or anvil member depending from a pivot having an approximately horizontal axis and over the surface of which plate a plurality of threads are adapted to pass, a plurality of tension members for separately pressing said threads against said plate to tension the threads, and means operable to swing said plate on its pivot into and out of active position with relation to said tension members and thereby apply or release tension upon all of said threads together.

7. In thread-tensioning means for sewing" machines or the like, the combination of a presser plate or anvil member depending from a pivot having an approximately horizontal axis and over the surface of which plate a plurality of threads are adapted to pass, a plurality of tension members for separately pressing said threads against said plate to tension the threads, adjusting means for separately determining the degree of pressure to be exerted by each member upon its thread, and means operable to swing said plate on its pivot into and out of active position with relation to said tension members and thereby apply or release tension upon all of said threads together.

8. In thread-tensioning means for sewing machines or the like, the combination of a presser plate or anvil member depending from a pivot having an approximately horizontal axis and over the surface of which plate a plurality of threads are adapted to pass, a plurality of tension springs for separately pressing said threads against said plate to'tension the threads, adjusting means overhanging said springs and adjustable. to

separately determine the degree of pressure to be exerted by each spring upon its thread,

and means operable to swing said plate on its pivot into and out of active position with 'of pressure to be exerted by its spring upon its thread, and means operable to swing said plate on its pivot into and out of active position with relation to said springs and thereby apply or release tension upon all of said threads together.

10. In thread-tensioning means for sewing machines, the combination of a movably supported presser plate or anvil, a plurality of flat spring members rigidly secured to a suitable support and each having a portion adapted to directly engage and yieldingly press a thread into direct contact with the surface of said plate to tension the thread, and means operable to move said plate into and out of active position with relation to said spring members collectively to thereby apply or release tension upon. all of the threads together,

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1 11. .In thread-tensioning means for sewing); machines, the combination of a movahly supported presser plate or anvil, a plurality of flat spring members: rigidly secured to a suitable support and each having a portion adapted to directly engage and yielclingly press a thread into direct contact with the surface of said plate to tension the thread adjustingineans for separately determining the degree of pressure to-he exerted by each ARTHUR A. MERBITT. 

